Research on single-phase power factor correction (PFC) rectification technology is moving in the trend of high efficiency and high power density, and the totem pole bridgeless PFC topology was proposed in responsive to this trend, as shown in FIG. 1. A totem pole bridgeless boost converter circuit system comprises an alternating current input voltage AC, a boost inductor L, four switches S1, S2, S3 and S4, a filter capacitor Co and a load Ro. In the positive half cycle of the alternating current input voltage AC, the switch S2 is always closed, the S1 is opened, the switch S4 is closed, the switch S3 is opened, in this case, it is a process that the current on the inductor L increases and energy is stored, after the energy storage process of the inductor L is completed, and when the switch S3 is closed and the switch S4 is closed, it is a process that the current on the inductor L decreases, and the inductor L releases energy; when the input AC voltage is in the negative half cycle, the switch S1 is always closed, the S2 is opened, the switch S3 is closed, and the switch S4 is opened, in this case, the current on the inductor is increasing constantly, and the inductor stores energy, after the energy storage of the inductor L is completed, the switch S4 is closed, the switch S3 is opened, and in this case, the current on the inductor decreases, and the inductor L releases energy.
In the abovementioned totem pole bridgeless PFC circuit system, due to the limits of the topology structure itself, the totem pole PFC cannot, like a two-way switch bridgeless PFC, use the fast recovery diode characteristics to improve the EMI, meanwhile, the hard-switching characteristics of the CCM mode cannot make it meet the industry's growing demand for high efficiency. To solve the abovementioned problems, it can use a topology based on the TCM (triangular current mode) mode and simplified from the totem pole, if it is controlled to achieve the full AC input voltage under the TCM mode, the ZVS (zero voltage switching) characteristics or VS (valley switching) characteristics in the full load range, it can meet requirements of high power density and high efficiency.
However, in the practice and research process of abovementioned control strategy, there are the following problems: in the existing totem pole converter circuit system, it needs to timely and accurately detect an inductor voltage reversal signal of the PFC for achieving the timing control of the power frequency switches S1 and S2 and the high frequency switches S3 and S4, so as to achieve the VS or ZVS control in the full input AC voltage and the full load range under the TCM mode. Otherwise, the switch might be conducted when there is still high voltage going through, and the efficiency of the totem pole bridgeless PFC is low.